题目内容：

The flight ____ because of the snowstorm,many passengers could do nothing but take the train
a.had been canceled b.have been canceled
c.were canceled d.having been canceled
选D 怎么分析?WHY?

优质解答

前后句子主语不一致
所以要用独立主格结构 ：逻辑主语+加分词的形式
这里The flight 是逻辑主语
having been canceled 是分词
因为暴风雪已经发生,所以用完成时